Remove Core Library JARs from `/system/framework`.

These JARs are part of the ART APEX, and are now located in
`/apex/com.android.art/javalib`. Remove the supernumerary copies in
`/system/framework` and save ~11 MiB on the system partition.

Test: Device boot test
Bug: 142944799
Change-Id: Ia6f58d858ecdb80c9701696b8f20d5fa2de0c2c7
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 50fff08..3aaf72c 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -690,6 +690,10 @@
 # Migrate preopt files from system_other for some devices
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system_other)
 
+# Remove Android Core Library artifacts from the system partition, now
+# that they live in the ART APEX (b/142944799).
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/framework/*.jar)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/main.mk b/core/main.mk
index a081be2..f808660 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1255,6 +1255,8 @@
   endef
 endif
 
+# TODO(b/142944799): Implement Java library absence check for Core Libraries.
+
 ifdef FULL_BUILD
   ifneq (true,$(ALLOW_MISSING_DEPENDENCIES))
     # Check to ensure that all modules in PRODUCT_PACKAGES exist (opt in per product)
diff --git a/target/product/runtime_libart.mk b/target/product/runtime_libart.mk
index 238b5e3..4a19ab4 100644
--- a/target/product/runtime_libart.mk
+++ b/target/product/runtime_libart.mk
@@ -20,11 +20,6 @@
 $(error TARGET_CORE_JARS is empty; cannot update PRODUCT_PACKAGES variable)
 endif
 
-# Minimal boot classpath. This should be a subset of PRODUCT_BOOT_JARS, and equivalent to
-# TARGET_CORE_JARS.
-PRODUCT_PACKAGES += \
-    $(TARGET_CORE_JARS)
-
 # Additional mixins to the boot classpath.
 PRODUCT_PACKAGES += \
     android.test.base \
@@ -37,6 +32,9 @@
 PRODUCT_PACKAGES += com.android.runtime
 
 # ART APEX module.
+# Note that this package includes the minimal boot classpath JARs (listed in
+# TARGET_CORE_JARS), which should no longer be added directly to
+# PRODUCT_PACKAGES.
 PRODUCT_PACKAGES += com.android.art
 PRODUCT_HOST_PACKAGES += com.android.art